煤矸石基地质聚合物混凝土梁高温性能研究

Study on high temperature performance of coal gangue based geopolymer concrete beams

首先制备干粉激发煤矸石基地质聚合物混凝土,基于此,采用有限元方法研究了煤矸石基地质聚合物混凝土梁的高温特性。建立了不同截面尺寸煤矸石基地质聚合物梁的有限元模型,研究了地质聚合物混凝土梁不同高温作用下的温度分布和变形;在不同高温工况下,研究了不同混凝土保护层厚度对地质聚合物混凝土梁的开裂荷载和极限荷载变化的影响规律;揭示了煤矸石基地质聚合物混凝土梁在高温时的变形、承载能力等特性的变化规律。研究表明:高温下混凝土梁底层和侧面的保护层厚度对内部钢筋的升温均有影响;温度升高,梁跨中的挠度增大,且增大截面尺寸可以有效降低高温时梁构件的变形。混凝土保护层厚度对梁的开裂荷载和极限荷载均有影响,增大保护层厚度对于提高高温后梁的承载力的作用是积极的,地质聚合物混凝土梁的截面尺寸越大,高温下梁的开裂荷载和极限荷载越大。

Firstly,dry powder activated coal gangue based geopolymer concrete was prepared.Based on this,the high temperature characteristics of coal gangue based geopolymer concrete beams were studied by finite element method.The finite element models of coal gangue based geopolymer concrete beams with different section sizes of coal gangue base material are established and the temperature distribution and deformation of geopolymer concrete beams under different high temperatures are studied.The influence of different thickness of concrete protective layer on cracking load and ultimate load of GPC beams was studied under different high temperature conditions.The variation law of deformation and bearing capacity of coal gangue based geopolymer concrete beams at high temperature has been revealed.The results show that the thickness of protective layer at the bottom and side of the geopolymer concrete beams has an effect on the temperature rise of internal reinforcement.With the increase of temperature,the deflection of beam span increases,and the increase of section size can effectively reduce the deformation of the beam members at high temperature.The thickness of the concrete protective layer has an effect on the cracking load and ultimate load of beams,and increasing the thickness of protective layer has a positive effect on improving the bearing capacity of beams at high temperature.The larger the section size of the geopolymer concrete beams is,the greater the cracking load and ultimate load of beams at high temperature is.